Apparatus for treating oil and gas bearing strata



June 7, 1949. s. D. SPRONG 2,472,445

APPARATUS FOR TREATING OIL AND GAS BEARING STRATA Filed Feb. 2, 1945 3 Sheets-Sheet 2 INVENTOR.

SEVERN D. SPQONG AT OQNEY June 7, 1949. s s o 2,472,445

APPARATUS FOR TREATING OIL AND GAS BEARING STRATA Filed Feb. 2, 1945 3 Sheets-Sheet 3 4 on. BEARING SHALE INVENTOR. SEVEQN 0. spnowe 4 BY fit? A IQNEY Patented June 7, 1949 UNITED STATES PATENT OFFICE APPARATUS FOR TREATING OIL AND GAS BEARING STRATA Delaware Application February 2, 1945, Serial No. 575,859

1 Claim.

My invention relates to improvements in methods of and apparatus for treating oil wells and oil-bearing structures, and the same has for an object to provide simple, eflicient and reliable method and means whereby oil present in a given area may be caused to flow and collect at one or more predetermined points from which it may thereupon be pumped or otherwise withdrawn.

Further, the invention has for an object to provide a simple, efflcient and comparatively inexpensive method and means whereby to restore wells which have .become under certain conditions blocked, depleted or dormant.

Further, the invention has for an object to provide an apparatus which may be readily inserted into a well to act upon the surrounding soil in order to restore or increase the productive capacity thereof.

Further, the invention has for an object to provide an apparatus which may be readily inserted into a well to heat the surrounding sub-surface soil or material in order to soften or dissolve any paraffin, bitumen or other substances which constrict the pores of the oil sand and thereby reduce the flow of oil into the well.

Further, the invention has for an object to provide an apparatus of the character specified including a heating element which may be energized in place from a source of supply located wholly without the well.

Further, the invention has for an object to provide a heating apparatus by relatively high frequency alternating electrical current which may be readily introduced into an existing oil well and rendered operative at any point within the depth of the well to locally engender heat which is transmitted to the sub-soil surrounding such point.

Further, the invention has for an object to provide an electro-magnetic heating apparatus for the purposes specified in which the heating element is energized or excited by alternating current of relatively high frequency in order to generate heat-creating eddy currents in the well casing, or in a casing embracing the heating element and suspended jointly with the heating element. such heating apparatus being provided with passages for the passage therethrough of the oil or other petroliferous materials and gas generated therefrom by the heat created by such heating apparatus.

Further, the invention has for an object to provide an apparatus comprising a plurality of mutually linked heating elements whereby the subsurface of the earth surrounding the well may be simultaneously heated at a plurality of separated 2 or spaced points throughout a given depth of the well for the purpose of generating heat locally at such points, whereby to soften, melt or dissolve any paraflln, bitumen or other substances tending to constrict, clog or seal the pores of such oilbearing soil.

Further, the invention has for an object to provide an apparatus which includes a plurality of electrically heated elements which may be energized from a source of current supply located without the well or shaft, and which may be heated singly or simultaneously for the purpose of transmitting heat to a plurality of separated points within the well or shaft to locally heat the surrounding oil or gas bearing structure, such as petroleum or petroliferous sands or shales, coal or lignite, in their natural and undisturbed condition of which the oil or volatile matter found or held in their natural state, may thereby be released and caused to flow to a provided means of escape and collection as the result of such subsurface retorting.

Other objects will, in part, be obvious, and. in part, are pointed out hereinafter.

To the attainment of the aforesaid and other objects and ends my invention consists in the novel features of construction, and in the combination, connection and arrangement of parts, and in the steps constituting the novel method hereinafter more fully described and pointed out in the claim.

In the accompanying drawings Figure l is a side elevation showing one embodiment of a heating element pursuant to my invention;

Fig. 2 is a diagrammatic view showing a section of an oil well or shaft and illustrating generally the operation of my heating element pursuant to my invention;

Fig. 3 is an enlarged central, vertical section on line 3-3 of Fig. 6;

Fig. 4 is a. plan view, partly in section on line [-4, of Fig. 1; this view shows four passageways through the heating element afforded by its mutually spaced pole pieces;

Fig. 5 is a transverse section on line 5-5 of Fig. 3;

Fig. 6 is a transverse section on line 6-6 of Fig. 3; this view also shows four passageways through the heating element afforded by its mutually spaced pole pieces;

Fig. 7 is an enlarged detailed side elevation of the upper portion of the electro-magnetic heating element and its supporting means, indicated in Figs. 1 and 3.

Fig. 8 is a side elevation of another embodiment of the invention, showing two or more heating elements in linked assembly, and a manner of supporting the same;

Fig. 9 is a vertical central sectional view of another embodiment of the invention, showing a length of casing embracing a heating element and supported jointly with the heating element;

Fig. 10 is a perspective diagrammatic view illustrating an application of my invention in the treatment of sub-surface oil bearing soil by the provision of a plurality of shafts into which my heating means is inserted at desired levels, whereby the therein contained oil may be caused to issue and be withdrawn by suitable means; and

Fig. 11 is a diagrammatic view, illustrating another application of my invention, in the treatment of oil-bearing shale by the provision of a plurality of shafts passing through such shale and communicating at their lower ends with a horizontal channel into which the oil present in the oil bearing shale is caused to flow by gravity, to be pumped or collected by suitable means.

In the drawings, Ill designates a heating element which as shown comprises a core II, see Fig. 4; formed of laminations I2 arranged in cruciform cross-section and which may include upper and lower parts l3, l4, respectively. The laminations I2 are shown arranged in four groups having their inner end portions terminating in pointed or triangular ends I3a, I3b, see also Fig. 5, separated by narrow intersecting air gaps I5, serving as through passages passing through the central zone of the heating element. I6 denotes layers or wrappings of suitable insulating material disposed about the core parts I2, l3; and I1 denotes heads of suitable insulating material disposed upon the upper and lower core parts I3, I4, also against the upper end lower projections or pole pieces l8, see Fig. 3, and the intermediate projection or pole piece ill of the core II.

The core laminations are secured together by any suitable means such as segmental plates or brackets 20 having angularly related end portions 2| engaging the outer vertical sides of the core projections or pole pieces I8, I9, and bolts 22 passing through the end portions 2i of the segmental plates 20 and core parts l3a, 13b. The' bolts 23 andnuts 24 serve to secure the core laminations l2 firmly clamped together at their upper and lower ends, and at their intermediate portions.

The upper and lower core parts I3, l4 are provided with suitable insulated coil windings 25, 26, the terminals 25a, 26a, see Figs. 7 and 9, of which are shown carried upwardly through openings in the webs of the segmental plates 20 and the spacing bar 21, to conductors 28, 29, respectively, leading to a suitable source of alternating electrical current.

The element I is suitably suspended, as by means of a yok 30, shown having its threaded ends extending downwardly through the webs of the plates 20 and secured at the underside thereof by nuts 3la. 32, see Figs. 1, 7, 8 and 9, denotes a hoisting cable whose upper end may be secured to a suitable winch or reeling mechanism, not shown, and its lower end provided with a hook 33 for detachably engaging the yoke 30 for supporting or suspending the heating element Ill within a well. The invention contemplates the use of tubular means of electromagnetic material disposed in close adjacency to the strata to be treated. Thus, Fig. 2 illustrates a well provided with a casing 34, of steel or other suitable magnetic material. For convenience of operation, the conductors 28, 29 may be secured at. suitable intervals to the hoisting cable 32, as by wrapplngs or clamping devices 35.

In the arrangement illustrated in Fig. 8, a plurality of heating elements such as above described, and shown two in number, are connected to one another by links, whereby such plurality of elements may be suspended one below the other to thereby provide sources of heat at a plurality of separate points in a shaft. The uppermost element is shown provided at its lower end with a yoke 36 secured to the lower segmental plates 20 of the respective heating elements, and the yoke 36 of the lower element I0 connected to the yoke 36 of the upper element III by a link 31. The terminals of the lower element are shown connected with the corresponding terminals of the upper element, and the leads connected thereto are shown carried upward to the bar 21, and thence to the conductors 28, 29, extending from the source of electrical supply.

In the employment of the embodiment of my invention illustrated in Figs. 1 through 8, inclusive, assuming that the well is provided with a steel or other magnetizable material, such as the casing indicated at 34 in Fig. 1, upon excitation of the electrical coils of my heating element, heat is engendered within the material of the casing at those portions thereof adjacent the heating element, whereby heat is conducted or otherwise transferred to the sub-soil surrounding the thus heated portion or portions of the well casing. When a succession of heating elements are employed, as is exemplified by Fig. 8, the localized heated portions of the well casing are increased in number and additively in extent of the length of the well casing, thereby enlarging the extent of the sub-soil which is raised in tem* perature.

A particularly advantageous application of my invention, assuming the well to be provided with a casing of magnetizable material, is in restoring an oil well which has become clogged by material such as paraflln or like constituents of crude oil, or other materials which are capable of being rendered fluid by heat. In the circumstance that such materials clog the well at the terminus of the well casing, my invention pos sesses outstanding merit in that the heating element may be lowered to substantially the lower end of the casing, whereby the heat thus engendered is localized at the vicinity of the clogging material, and the degree of heat transferred ,to the clogging material is under complete control by suitable regulation of the applied voltage of the alternating current. In the circumstance where the clogging material may be located outwardly of the lower terminus of the well casing, my heating element is likewise eflicacious in that it may be placed in suspension at such intermediate location or locations to thereby heat, melt and cause to flow through the sub-soil to the lower terminus of the well casing from which it may be pumped or otherwise collected.

In the arrangement illustrated at Fig. 9, the construction of the heating element is as hereinabove described. The apparatus of this construction is designed for use in wells or shafts which are not provided with a, therewith surrounding tubular casing or lining. Pursuant to the arrangement illustrated by Fig. 9, my heating element is provided with a perforated sleeve Illa of suitable material and having a length to embrace the field of. magnetic flux of the heating element. The sleeve Ifla thus constitutes tubular means of electromagnetic material associated with the heating element. The assembly of electromagnetic coil and tubular sleeve Illa is selectively located at the desired point in the shaft where the heat engendered in the tubular sleeve "la is to be applied. In other words, the described assembly, including the sleeve Illa, is disposed in close adjacency to the strata to be treated.

Pursuant to my stated assembly of heat generating and therewith enclosing casing length, applications of heat to sub-surface soil is carried out in a well which is not provided with a. casing of magnetizable material or devoid of any casing, in the latter situation affording the transfer of heat directly to the sub-surface soil.

Fig. illustrates another application of my invention namely in the release of oil from subsurface oil-bearing strata, such as oil-bearing sand located below sandstone and/or soil overburdened. As one manner of carrying out my invention in such situation, a vertically extending well 41 is bored through such soil or other overburden indicated at 40 -to a depth within such oil-bearing sub-strata; such well 4| serves as the oil withdrawing well and for such purpose may be equipped with a suitable casing to afiord the insertion therein of suitable pumping or other withdrawing equipment. Borings 42, 42, etc., are drilled in suitable number and at determined 10- cations surrounding the withdrawing boring 4|. Assemblies of my heating element, such as indicated in Fig. 9, denoted Ilia, are lowered into the borings 42, 42, etc. at determined, variant levels within such oil-bearing substrata by means of suspension cables, indicated at 32, to thereby liquefy the releasable oil constituents within such oil-bearing substrata, rendering the same withdrawable by the suction efiect produced by the pump or equivalent withdrawing equipment installed in the casing 4|. Such operation is in the nature of retorting or distillation under subterraneous conditions.

Another application of my invention is diagrammatically shown in Fig. 11, pursuant to which borings or casing-enclosed wells are drilled through oil-bearing shale or other strata or overburden. As is indicated in Fig. 11, borings 45, 45, etc., are drilled through such oil-bearing shale or other oil-bearing deposit. My heat generating devices indicated at Illa, Illa, etc. are lowered by suspension cables indicated at 32 in these vertical borings 45, 45, etc. at determined variant depths to thereby liquefy the oily constituents of the petroliferous structure in this instance to cause the same to flow downwardly through the respective borings 45 into a therewith lowerly disposed channel or channels indicated at 48, bored from one side of the substrata at draining slope and to communicate with the lower ends of the vertical borings 45, 45, through which channel or channels 46 the oil is withdrawn.

The heating engendered by my heating element or assembly, per se, may be supplemented by the flow of air' under compression through the vertical borings, whereby such pressure air is heated simultaneously with the direct heating of the adjoining oil-bearing sub-strata, and being under compression such heated air is forced and distributed through the crevices and pores of the sub-strata, thus expanding the zones of heat treatment of the sub-strata.

In such procedure, the pressure air is afforded passage through my heat generating device, either in the form of a single heating element or a succession of linked heating elements, by the provision of the clearances between the windings and between the extensions of the pole pieces and in contact with and about the respective casing lengths of the respective coils of the heating element or elements.

Water, under gravity or positive pressure, supplied to the vertical borings, may also be employed as a heat-transferring agent supplemental to the directheat generated by one or more of my heating elements. As in the employment of air as a supplemental heat transferring agent, the water heated by my heating element or elements by passage through the clearances about the windings and pole pieces and the casing lengths of the respective heat generating elements.

In carrying out my method in subjecting petroliferous sub-strata or other petroliferous earth structures to elevated temperature, gaseous constituents of such petroliferous structure are evolved. For the purpose of collecting such gaseous constituents, the casings of the wells employed. such as the collecting well 4| and its associated wells indicated in Fig. 10, are perforated and provided at their respective upper ends with a cap for the purpose of confining such evolved gaseous constituents within such wells. Such cap may be of two-part assembly, having a central opening, for the passage therethrough of the electrical and suspension cables of my electrical heating means, and another opening, which may be threaded for connection with the threaded end of a pipe or equivalent for leading the gaseous constituents to a suitable condensing and scrubbing apparatus, as will be understood by those skilled in the art.

As appears from the foregoing, the invention provides for apparatus of high efficiency for the treating of selected zone or zones of sub-surface strata comprising a heating element, preferably powered by alternating electric current of relatively high frequency, such heating element comprising a central core which is disposed in vertical position when the heating element is suspended within the bore leading to the stratum or strata desired to be heated, said heating element further comprising a plurality of mutually vertically spaced sets of pole pieces, each set comprising a plurality of mutually horizontally spaced pole pieces and electrical windings surrounding such central zone, the lateral periphery of which is materially spaced from the lateral faces of such pole pieces whereby to provide passages through said heating element about said windings and between said pole pieces, for aifording the fiow therethrough of the oil or other petroliferous material and the gases generated by the heating of such stratum or strata. Such heating element is preferably further provided with a central core formed of component core parts mutually spaced from one another to provide therebetween passageways for the flow therethrough of such fluidrendered oil and other petroliferous material and the thus generated gases.

Whereas I have described and illustrated my invention by reference to specific embodiments thereof, it is apparent that my invention is not limited thereto, as appears from the hereto appended claim.

I claim:

Means for heating sub-surface strata for the release of oil and other petroliierous material con- 7 tained therein, said means comprising: electromagnetic heating means provided with a vertitally extending central laminated core and a plurality of mutually vertically spaced sets of pole pieces, each set comprising a plurality of mutually horizontally spaced pole pieces and electrical windings surrounding said central core the lateral periphery of which is materially spaced from the lateral faces ofsaid pole pieces whereby to provide passages through said heating element about said windings and between said pole pieces; in combination with a tubular member of electromagnetic conducting material disposed about said heating element in operative juxtaposition with the lateral faces of its said plural pole pieces, said tubular member being provided with perforations; and means for suspending said heating element within a bore leading to the sub-surface strata in close adjacency to said tubular member and the strata to be treated.

SEVmN D. SPRONG.

8 aura-amass crrm UNITED STATES PATENTS Number Name Date 432,050 Kammeyer July 15, 1890 1,309,721 Drinkern July 15, 1919 1,354,757 Popcke et a1 Oct. 5, 1920 1,472,504 Thomson Oct. 30, 1923 1,854,322 White Apr. 19, 1932 2,134,610 Hogg Oct. 25, 1938 2,244,256 Looman June 3, 1941 2,281,334 Bomes Apr. 28, 1942 2,288,038 Somes June 30, 1942 2,302,774 Jarvis Nov. 24, 1942 

